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71 Cards in this Set
- Front
- Back
Photosynthesis equation
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Water + CO2 + energy = oxygen + C6H1206
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How is chemical energy stored in plants?
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- soluble CHOs for immediate energy - digestible (sucrose and starch)
- structural CHOs - cannot be used for energy - cellulose |
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what is the most abundance carbohydrate in the world?
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-cellulose
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principle form in which soluble CHOs are transported and stored
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-sucrose and starch
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respiration equation
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C6H1206 + O2 = CO2 + H20 + energy
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what is energy used for in plants?
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-assimilation
-maintenance -growth |
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assimilation
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-synthesis of compounds (e.g. cellulose, etc.)
-active transport -mineral uptake |
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energy used for maintenance in plants
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-respiration of living material
-respiration during dormancy |
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vegetative growth
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-regrowth after dormancy
-bud formation -regrowth after disturbance |
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reproductive growth
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-elevation of apical meristem
-apical dominance -flower and seed formation |
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factors affecting photosynthesis and respiration
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-water
-leaf area -sunlight -temperature -carbon dioxide -soil nutrients |
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how does grazing alter plant physiological activities?
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-change leaf area
-change soil nutrient availability -removal of meristematic tissue -compensatory photosynthesis |
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compensatory photosynthesis
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-after grazing, photosynthetic rate increases (15-50%) in some plants
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factors of plant growth considered in planning range activities
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-dormant period is least damaging
-period of growth initiation is intermediate relative to negative effects of defoliation -most critical period for foliage removal is from floral initiation through seed development |
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how are range activities harmful to plants during the dormant period?
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-soil compaction
-damage to meristems |
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effects of range activities in spring intermediate due to...
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-low energy demands
-moitsure and nutrients largely available -lots of time to recover -meristems not accessible |
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floral initiation through seed development
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-high energy demands for reproductive parts and daily maintenance
-limited available nutrients and water |
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three kinda os meristems
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-apical (top of plant, flower, or seed)
-axillary (nodes from which new leaves grow0 -intercallary (base of petioles and leaves, internodes) |
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apical dominance
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-apical meristem releases hormones to keep axillary meristems in dormant state
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-when apical meristem removed
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-axillary buds begin to make a new tiller or leader
-axillary buds change into apical buds, produce flowers and fruit |
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after defoliation
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-growth from axillary buds
-expansion of intercallary meristems |
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growth in dicots (forbs and woodies)
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first - new leaves
second - new stems ----expansion from base to tip |
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growth in grasses
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-expansion from tip to base
--first - intercallary meristems --second - new leaves --third - new stem/tillers |
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apical meristem stays at base until flowering, then expansion of internodes causes
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-bolting
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positive effects of grazing
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-compensatory growth
-tillering -nutrient cycling -change sunlight access -remove respiratory materail (save water) -seed dispersal -increase in diversity -reduction of fuel for fire -reduce mulch |
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negative effects of grazing
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-removal of photosynthetic material
-removal of meristems and root crown -removal of seeds -transport disease -ground compaction -soil compaction and erosion -spread of weeds -reduce mulch |
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grazing vs. fire
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-selective, leaves remnants
-easy to control -occurs year-round -slow rate -changes communities |
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grazing avoidance mechanisms
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-thorns, prickles, spines
-growth form (sodgrass vs. bunchgrass, or prostrate) -plant size -location of meristems -live:dead ratio of culms or shoots |
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leaf replacement potential
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-rate at which a plant reestablishes leaves
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CHOs needed in plant for...
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-reestablishing photosynthetic material
-seed production -root growth |
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most energy for regrowth comes from...
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-current photosynthesis
-NOT stored reserves |
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three major factors determining nutritive value of plants
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-cell structure (cell wall: cell contents)
-degree of lignification -anti-quality agents |
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NDF
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-neutral detergent fiber
-in cell walls |
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why are fruits, seeds, and flowers generally more nutritious?
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-higher levels of cell contents (solubles)
-seeds also contain significant levels of fat |
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why are leaves more nutritious than stems?
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-lower cell wall: cell content ratio
-more soluble energy and nutrients |
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in shrubs, current season growth more nutritious than old growth. why?
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-CHOs stored in stems
-old stems not as efficient or metabolically active, and have more lignin that gradually turns to wood |
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why does nutritive value decrease as a plant matures?
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-reduced cell contents
-increased lignification and structural CHOs -decrease in ratio of leaves to stems -leaching of nutrients by rain in dormancy |
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browse
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-portion of shrubs used for forage
-generally includes leaves and current season's twigs |
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nutrition during growing and dormant season
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-forbs>grasses>shrubs = growing season
-browse important for nutrients |
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warm season (c4) plants less nutritious than cool season (c3) plants because...
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-more schlerenchyma, epidermis, vascular tissue
-cell walls more lignified |
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effects of high temperature on plants
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-decrease water-soluble CHOs and protein levels
-lignification and maturation occur more quickly |
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moisture stress
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-moderate moisture stress increases nutritive value by delaying maturation
-severe moisture stress hastens translocation of nutrients to roots and senescence (dormancy) |
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fertile soils may
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-delay maturity and increase leaf:stem ratios
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high levels of soil nitrogen
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-increase protein content of plants
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factors influencing grazing tolerance
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-intensity
-frequency -time (season) -competition from neighboring plants |
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cecal fermenters or ruminants can eat lower quality food?
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-cecal fermenters
-greater rate of passage -can eat more |
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fermentation
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-microbes break down cellulose
-release volatile fatty acids as byproduct -VFAs absorbed, trnaported to liver -converted to useable energy - glucose, acetyl coA, oxyacetyl acid, fat |
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ruminants - examples
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-cows, sheep, deer, bison, elk, pronghorn
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cecal fementers - examples
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-horses, rabbits, some rodents
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protein for ruminants vs. cecal fermenters
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-rumen is BEFORE small intestine (cecum after SI) s microbes can be digested for protein
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on yearly basis, what requires greatest amount of energy by the animal?
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-maintenance = basal metabolism + minimum movement + foraging
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four greatest energy requirements in animals
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-maintenance
-reproduction -lactation -growth |
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energy percentage comparisons: standing vs. sitting, range vs. stable-fed
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-15% more energy required for standing than sitting
-40-46% more energy for range animals than stall=fed |
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grazers and roughage feeders
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-eat mostly grass, isn't as nutritious as forbs but more abundant
-cattle, musk oxen, bison |
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intermediate feeders
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-flexible in diet habits
-may choose all grass when it is young, then switch to forbs and shrubs later in season -moose, sheep, goats, elk |
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concentrate selectors
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-all monogastrics - cannot digest cellulose, must choose high quality diet
-deer, giraffe, rabbit -special harvesting skills like small nose/mouth |
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small or large - which must subsist on higher quality diets?
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-smaller animals
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stocking conservatively
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-ensures supply and allows selection
-reduces energy requirements for grazing |
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manipulating vegetation to meet animal needs
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-plant introduced pastures to provide abundance high quality forage during particular season
-manage for palatable shrubs -manage for plant diversity |
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how do grazing animals cope with periods of low quality forage?
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-build up fat when forage quqliaty is high
-lower BMR -nitrogen recycling -soil ingestion -supplementation |
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why is energy rarely econmical to supplement?
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-use of range vegetation generally decreases
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major operations expense confronting range livestock industry
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-supplementation
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high quality energy
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-grains
-impactical except under drought or heavy snow -young animals can be permanently stunted if undernutrition |
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low quality energy
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-hay or straw
-supplemented when animals cannot meet daily dry matter requirements (winters, droght) -energy source - cellulose |
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high protein feeds
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-alfalfa, cottonseed meal, soybean meal
-use of range may actually increase with N supplementation |
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non-protein nitrogen
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-urea and biuret
-lower cost than true protein -made into protein by rumen microbes -can be used to meet 1/3 total protein requirements |
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types of toxins
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-cyanide compounds
-alkaloids -fungal endophytes -nitrate -tannins and phenolics -terpenes |
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what is range management?
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-the use and stewardship of rangeland resources to meet goals and desires of humans
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7 concepts of rangeland management
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-rangelands are renewable resources
-rangelands are managed by extensive and ecological principles -produce variety of products for multiple use -must be managed to maintain soil and water quality and health -chance through succession and disturbance -only constant is change -many important public concerns across multiple ownerships |
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what is the basis of rangeland management?`
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-monitoring
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most important elements of monitoring
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-committment to monitor
-interpretation of data -making management changes if needed |